1. Field of the Invention
The present invention relates to an endoscope system which an insertion portion of an endoscope is inserted from an insertion opening of an object to observe an inner surface of the object.
2. Description of the Related Art
In an endoscope, as a light source configured to illuminate an inner surface of an object which is an observation target, a light source having a small luminous point such as a laser or a light source that radiates light having relatively high energy like ultraviolet light or blue light is used.
With respect to radiated light radiated from such a light source apparatus, a maximum permissible exposure (MPE) of a human body largely varies depending on eyes and skin. That is, the MPE for the eyes has a value which is several score times larger than the MPE for skin. Thus, in a medical endoscope, there has been desired detection means for detecting whether an insertion portion of an endoscope having an illumination light emitting portion arranged at a distal end thereof. When such detection means is provided, a light volume upper limit based the MPE for eyes is set for the outside of a body, a light volume upper limit for skin is set for the inside of a body, and control can be effected so that the light source can emit light with a light volume required for observation.
Further, for the purpose of preventing a subject from feeling annoyed with glare, detection means for detecting that an insertion portion is present inside or outside a body is desired.
On the other hand, in an industrial endoscope, to extend life duration of a light source apparatus or achieve power saving, when the insertion portion is present outside an observation target object, detection means for detecting the inside or the outside of the observation target object is likewise desired for the purpose of stopping or dimming the light source.
In contrast, Japanese Patent No. 4316118 discloses a technology that detects the inside of a living body or the outside of a living body by detecting flicker of a fluorescent lamp by means of a detector disposed at a distal end of a scope.
However, the technology disclosed in Japanese Patent No. 4316118 uses the flicker of the fluorescent lamp. Therefore, in the medical endoscope cannot detect that the insertion portion is present in the inside or the outside of a body in an examination room where the fluorescent lamp is not used. On the other hand, in the industrial endoscope, whether the insertion portion is present in the inside or the outside of the observation target object cannot be detected in an outdoor usage environment. Further, even in a case where a fluorescent lamp is provided in a room, if any other illumination apparatus is also provided, flicker of the fluorescent lamp is masked by light from the apparatus and may not be detected with certainty.
In view of the above-described problems, it is an object of the present invention to provide an endoscope system that can detect with certainty that an insertion portion of an endoscope is present inside or outside an object.